The Olimpia tunnel on the A26 reopened this morningon the northbound carriageway between the Alessandria Sud and Casale Monferrato Sud junctions. 890 metres long and built in the 1970s without waterproofing, since June 2023 it has been the subject of one of the most important interventions of the Assessment Plan for tunnels on the motorway network under concession to Aspi, thanks to which the nominal life of the tunnel has been extended by 50 years.
Amplia’s commitment
The reopening of the tunnel to traffic was made possible first and foremost by thecommitment of approximately 55 people at Amplia – the construction company of the Autostrade per l’Italia Group – who worked 24/7 on multiple shifts, using approximately 25 vehicles (excavators, PLEs, bobcats, truck cranes, generators, light towers, jumbos, sweepers, fog cannons, scarifiers, finishers, compressors, mixers, frame laying machines, mechanical cutters, hydrodemolition machines, spritz pumps) for a total of over 300,000 hours.
A new waterproofing system
The intervention consisted of the partial demolition of the existing cladding along the entire length of the dome and replacement with a structural concrete shell built with the simultaneous use of three specially sized mobile formworks that allowed for casting on site. The tunnel was also equipped with a waterproofing and drainage system for infiltration water.
An innovative highway de-icing system
The peculiarity of this arch is the‘installation on a Tun.Re.Fit segment, an innovative highway de-icing system tested and created with researchers from the Polytechnic of Turinwhich uses the heat from the rock mass above the cap to heat the emergency lane outside the entrance on the Gravellona Toce side. Almost 1000 meters of geothermal pipes have been inserted into the newly constructed lining of the Olimpia tunnel, which has thus become the first energy tunnel in the world to be made so after its construction. The heat thus recovered is transferred to the external road surface to heat it during the coldest periods of the year.
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